Classifications

• • C—CHEMISTRY; METALLURGY
  • C10—PETROLEUM, GAS OR COKE INDUSTRIES; TECHNICAL GASES CONTAINING CARBON MONOXIDE; FUELS; LUBRICANTS; PEAT
  • C10M—LUBRICATING COMPOSITIONS; USE OF CHEMICAL SUBSTANCES EITHER ALONE OR AS LUBRICATING INGREDIENTS IN A LUBRICATING COMPOSITION
  • C10M3/00—Liquid compositions essentially based on lubricating components other than mineral lubricating oils or fatty oils and their use as lubricants; Use as lubricants of single liquid substances
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08K—Use of inorganic or non-macromolecular organic substances as compounding ingredients
  • C08K5/00—Use of organic ingredients
  • C08K5/0008—Organic ingredients according to more than one of the "one dot" groups of C08K5/01 - C08K5/59
  • C08K5/0025—Crosslinking or vulcanising agents; including accelerators
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
  • F16F—SPRINGS; SHOCK-ABSORBERS; MEANS FOR DAMPING VIBRATION
  • F16F9/00—Springs, vibration-dampers, shock-absorbers, or similarly-constructed movement-dampers using a fluid or the equivalent as damping medium
  • F16F9/006—Springs, vibration-dampers, shock-absorbers, or similarly-constructed movement-dampers using a fluid or the equivalent as damping medium characterised by the nature of the damping medium, e.g. biodegradable
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08G—MACROMOLECULAR COMPOUNDS OBTAINED OTHERWISE THAN BY REACTIONS ONLY INVOLVING UNSATURATED CARBON-TO-CARBON BONDS
  • C08G77/00—Macromolecular compounds obtained by reactions forming a linkage containing silicon with or without sulfur, nitrogen, oxygen or carbon in the main chain of the macromolecule
  • C08G77/04—Polysiloxanes
  • C08G77/14—Polysiloxanes containing silicon bound to oxygen-containing groups
  • C08G77/16—Polysiloxanes containing silicon bound to oxygen-containing groups to hydroxyl groups
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08G—MACROMOLECULAR COMPOUNDS OBTAINED OTHERWISE THAN BY REACTIONS ONLY INVOLVING UNSATURATED CARBON-TO-CARBON BONDS
  • C08G77/00—Macromolecular compounds obtained by reactions forming a linkage containing silicon with or without sulfur, nitrogen, oxygen or carbon in the main chain of the macromolecule
  • C08G77/04—Polysiloxanes
  • C08G77/14—Polysiloxanes containing silicon bound to oxygen-containing groups
  • C08G77/18—Polysiloxanes containing silicon bound to oxygen-containing groups to alkoxy or aryloxy groups
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08G—MACROMOLECULAR COMPOUNDS OBTAINED OTHERWISE THAN BY REACTIONS ONLY INVOLVING UNSATURATED CARBON-TO-CARBON BONDS
  • C08G77/00—Macromolecular compounds obtained by reactions forming a linkage containing silicon with or without sulfur, nitrogen, oxygen or carbon in the main chain of the macromolecule
  • C08G77/04—Polysiloxanes
  • C08G77/20—Polysiloxanes containing silicon bound to unsaturated aliphatic groups
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08G—MACROMOLECULAR COMPOUNDS OBTAINED OTHERWISE THAN BY REACTIONS ONLY INVOLVING UNSATURATED CARBON-TO-CARBON BONDS
  • C08G77/00—Macromolecular compounds obtained by reactions forming a linkage containing silicon with or without sulfur, nitrogen, oxygen or carbon in the main chain of the macromolecule
  • C08G77/42—Block-or graft-polymers containing polysiloxane sequences
  • C08G77/44—Block-or graft-polymers containing polysiloxane sequences containing only polysiloxane sequences
• • C—CHEMISTRY; METALLURGY
  • C10—PETROLEUM, GAS OR COKE INDUSTRIES; TECHNICAL GASES CONTAINING CARBON MONOXIDE; FUELS; LUBRICANTS; PEAT
  • C10M—LUBRICATING COMPOSITIONS; USE OF CHEMICAL SUBSTANCES EITHER ALONE OR AS LUBRICATING INGREDIENTS IN A LUBRICATING COMPOSITION
  • C10M2229/00—Organic macromolecular compounds containing atoms of elements not provided for in groups C10M2205/00, C10M2209/00, C10M2213/00, C10M2217/00, C10M2221/00 or C10M2225/00 as ingredients in lubricant compositions
  • C10M2229/04—Siloxanes with specific structure
  • C10M2229/041—Siloxanes with specific structure containing aliphatic substituents
• • C—CHEMISTRY; METALLURGY
  • C10—PETROLEUM, GAS OR COKE INDUSTRIES; TECHNICAL GASES CONTAINING CARBON MONOXIDE; FUELS; LUBRICANTS; PEAT
  • C10M—LUBRICATING COMPOSITIONS; USE OF CHEMICAL SUBSTANCES EITHER ALONE OR AS LUBRICATING INGREDIENTS IN A LUBRICATING COMPOSITION
  • C10M2229/00—Organic macromolecular compounds containing atoms of elements not provided for in groups C10M2205/00, C10M2209/00, C10M2213/00, C10M2217/00, C10M2221/00 or C10M2225/00 as ingredients in lubricant compositions
  • C10M2229/04—Siloxanes with specific structure
  • C10M2229/045—Siloxanes with specific structure containing silicon-to-hydroxyl bonds
• • C—CHEMISTRY; METALLURGY
  • C10—PETROLEUM, GAS OR COKE INDUSTRIES; TECHNICAL GASES CONTAINING CARBON MONOXIDE; FUELS; LUBRICANTS; PEAT
  • C10M—LUBRICATING COMPOSITIONS; USE OF CHEMICAL SUBSTANCES EITHER ALONE OR AS LUBRICATING INGREDIENTS IN A LUBRICATING COMPOSITION
  • C10M2229/00—Organic macromolecular compounds containing atoms of elements not provided for in groups C10M2205/00, C10M2209/00, C10M2213/00, C10M2217/00, C10M2221/00 or C10M2225/00 as ingredients in lubricant compositions
  • C10M2229/04—Siloxanes with specific structure
  • C10M2229/046—Siloxanes with specific structure containing silicon-oxygen-carbon bonds
• • C—CHEMISTRY; METALLURGY
  • C10—PETROLEUM, GAS OR COKE INDUSTRIES; TECHNICAL GASES CONTAINING CARBON MONOXIDE; FUELS; LUBRICANTS; PEAT
  • C10M—LUBRICATING COMPOSITIONS; USE OF CHEMICAL SUBSTANCES EITHER ALONE OR AS LUBRICATING INGREDIENTS IN A LUBRICATING COMPOSITION
  • C10M2229/00—Organic macromolecular compounds containing atoms of elements not provided for in groups C10M2205/00, C10M2209/00, C10M2213/00, C10M2217/00, C10M2221/00 or C10M2225/00 as ingredients in lubricant compositions
  • C10M2229/04—Siloxanes with specific structure
  • C10M2229/047—Siloxanes with specific structure containing alkylene oxide groups
• • C—CHEMISTRY; METALLURGY
  • C10—PETROLEUM, GAS OR COKE INDUSTRIES; TECHNICAL GASES CONTAINING CARBON MONOXIDE; FUELS; LUBRICANTS; PEAT
  • C10M—LUBRICATING COMPOSITIONS; USE OF CHEMICAL SUBSTANCES EITHER ALONE OR AS LUBRICATING INGREDIENTS IN A LUBRICATING COMPOSITION
  • C10M2229/00—Organic macromolecular compounds containing atoms of elements not provided for in groups C10M2205/00, C10M2209/00, C10M2213/00, C10M2217/00, C10M2221/00 or C10M2225/00 as ingredients in lubricant compositions
  • C10M2229/04—Siloxanes with specific structure
  • C10M2229/048—Siloxanes with specific structure containing carboxyl groups
• • C—CHEMISTRY; METALLURGY
  • C10—PETROLEUM, GAS OR COKE INDUSTRIES; TECHNICAL GASES CONTAINING CARBON MONOXIDE; FUELS; LUBRICANTS; PEAT
  • C10N—INDEXING SCHEME ASSOCIATED WITH SUBCLASS C10M RELATING TO LUBRICATING COMPOSITIONS
  • C10N2020/00—Specified physical or chemical properties or characteristics, i.e. function, of component of lubricating compositions
  • C10N2020/01—Physico-chemical properties
• • C—CHEMISTRY; METALLURGY
  • C10—PETROLEUM, GAS OR COKE INDUSTRIES; TECHNICAL GASES CONTAINING CARBON MONOXIDE; FUELS; LUBRICANTS; PEAT
  • C10N—INDEXING SCHEME ASSOCIATED WITH SUBCLASS C10M RELATING TO LUBRICATING COMPOSITIONS
  • C10N2040/00—Specified use or application for which the lubricating composition is intended
  • C10N2040/08—Hydraulic fluids, e.g. brake-fluids

Definitions

• This elastomer is characterized by a combination of a high cross-link density and a high proportion of free chain ends. lt crumbles to a powder under high shear stress, but has the unique property of flowing like a viscous fluid through a narrow orifice. It is useful in hydraulic impact absorbers and other hydraulic systems.
• Silicone fluids have been used in hydraulic shock absorbers because of their ability to dissipate energy by flowing through an orifice. They have the disadvantage that they must be used in closed systems to avoid loss by gravity. Even the smallest leak will permit deterioration over a period of time. Nevertheless, up till now no other materials have been found suitable in such application.
• elastomers and other materials have some impact-absorbing ability because of their ability to absorb energy by elastic deformation. 1t is also true that most elastomers can be forced through an orifice if subjected to enough pressure. In the process, however, all previously known elastomers become so thoroughly degraded that they can not be used a second time in the same system. The degradation is to some extent a mechanical breakdown from the high shear stress involved, but mainly it is chemical degradation caused by the high temperatures generated.
• Silicone elastomers are desirable materials for such an application because of their highthermal stability. Also they have a high compressibility, which tends to smooth out peaks in the stress-strain curve.
• none of those known heretofore have been suitable. They can be forced through an orifice, thereby being broken down into small particles, but these are relatively hard and do not easily flow back into their original position. Oil has been added as a plasticizer to overcome these disadvantages; however, it has not been very successful, since the oil bleeds from the elastomer and eventually leaks out of the system.
• an object of this invention to provide a hydraulic elastomer.
• Anotherobject of this invention is to provide a cross-linked silicone elastomer that is easily deformed under pressure and that breaks down into soft particles under high shear, said particles having the property of flowing under pressure, but not under theinfluence of gravity alone.
• Still another object of this invention is to provide a siliconefluid that is curable to such an elastomer.
• Afurther object of this invention is to provide a method for curing said fluid to said elastomer.
• Silicone fluids that may be used in the practice of this invention are linear siloxane copolymers having the general formula The molecular weight may vary between about 20,000 and 200,000, corresponding with viscosities between l000 and 1,000,000 centipoises (cp) at 25"C.
• the amount of methylvinylsiloxane units may vary from about 0.1 toiabout 0.9 mole percent. The optimum amount varies inversely;with the chain length.
• Vinyl is mole percent of methylvinylsiloxane, and V is the viscosity in cp. Vinyl” may be as much as 0.05 mole percent lower or 0.10 mole percent higher without departing from the optimum range. In mathematical terms, then, the optimum range is given by the relation:'
• Vinyl 4.8/log v c the cured elastomers are not as good as when the viscosity of the fluid is at least 5,000 cp. That is, the hardness of the elastomer and its resistance to flow are below. the desired range.
• The-preferred range is thus between a viscosity of from 5000 cp, with 0.57 mole percent Vinyl, to 30,000 cp, with 0.34 mole percent Vinyl.”
• the optimum range is from 10,000 to 15,000 cp with about 0.45 mole percent of methylvinylsiloxane and a molecular weight of about 60,000.
• the fluids of this invention may be prepared by any conventional method known in the art for preparing silicone polymers, such as condensation of short-chain hydroxy-terminal polymers, acid-catalyzed equilibration and base-catalyzed equilibration. 1n a basecatalyzed equilibration a mixture of cyclic oligomers of dimethylsiloxane, cyclic oligomers containing methylvinylsiloxane, alone or in combination with dimethylsiloxane', and a short-chain siloxane containing trimethylsiloxy end groups is heated to a temperature of from to C. with a fugitive catalyst such as tetramethylammonium hydroxide.
• a fugitive catalyst such as tetramethylammonium hydroxide.
• peroxide used for curing is important.
• Peroxides that generate acyloxy radicals, especially diacyl peroxides such as benzoyl peroxide, are relatively undersirable because they are strong hydrogen abstractors
• the degree of cross-linking is determined largely by the amount of peroxide and the temperature employed in the vulcanization.
• Vinyl-specific peroxides on the other hand,”generate cross-links through-the vinyl groups, and the degree of cross-linking depends primarily on the number of vinyl groups.
• Vinyl-specific peroxides are characterized by the fact-that their initial decomposition products are weight of the peroxide, as little'as 0.l percent or as much as 1.5 percent may be used. The preferred range is from 0.3 to 0.8 percent and more preferably about 0.5 percent.
• One class of vinyl-specific peroxides consists of tertiary alkyl peroxides.
• the simplest members of this I class such as tertiary butyl peroxide and tertiary amyl for long-term storage.
• peroxides having very low volatility at room temperature.
• the molecules have at least 14 carbon atoms, as in dicumylperoxide.
• Peroxides with two or more peroxy groups are often preferred. These include peroxides such as bis-(tbutylperoxyisopropyl)-benzene, bis-(t-butylperoxyiso propyl)-ethane, and -bis-(t-butylperoxyisopropyl)- acetylene. These are tertiary alkyiperoxides in the sense that every peroxidic oxygen atomis attached to a tertiary carbon atom. 4 i
• Suitable vinyl-specific peroxides may be described as diperoxy ket'als. Suitable examples peroxide, are chemically satisfactory but too'volatile mally solid peroxides it is sometimes desirable to pre-.
• the silicone fluid it is heated with the peroxidefor a length of time and ma temperature appropriate, to the peroxide.
• Minimum cures require a time equal to at least one half-life of the peroxide. Better resultsare obtainedafter 2 or 3 half-lives, and full cures require at least 5 to half-lives. Longer heating will'not causeany bad effects because the silicones are stable at temperatures above 200-C., and the preferred peroxides do not generate acidic by-products.
• . .Bis-(t-butylpcroxyiSopropyl)-ethanc of these are l,l-di-t-butylperoxy-3,3,5-trimethylcyclohexane and n-butyl 4,4-di-t-butylperoxyvalerate.
• Examples include shock absorbers, fluid couplings, braking systems, vibration dampers, rate-control devices and many others.
• the same elastomers work well in each of these.
• the optimum range of usable fluids may be slightly different from those described above. In almost all cases however, it will be found that the optimum range will lie within the boundaries of the preferred range given above. That is, the viscosity of the fluid will lie between 5,000 and 30,000 cp and the value of 'C'in equation (2) will lie between 0.53 and abo ve'0C. Still higher temperatures maybe used if upto 10 percent of water is present. Generally one recrystallization is sufficient.
• the product issatisfactorily pure if the absorbance at 240 nm is no stronger than the absorbance at'260nnm.
• the fluidlike properties develop as the elastomer is broken down into small particles.
• the size of the particles is not critical, but for optimum reproducibility they should be less than one millimeter in diameter.
• Hardness is determined with a Shore A durometer on A inch buttons cured, typically, for minutes at 350F. (ASTMD-395 Method B). Optimum results are obtained if the Shore A hardness is between 1 l and 14. Under certain conditions fairly good results may be obtained with elastomers that have a Shore A hardness as low as 9 or as high as l6.
• the cured elastomer may becliaracterizetl chemically. It contains an unusually large number of free ends, i.e. terminal segments. that are not involved in the cross-linking process. Given a fluid in the molecular weight range of 20,000 to 200,000 and given that there are two end groups per molecule, the number of end groups can be calculated as lying between 0.074 and 0.74 per 100 silicon atoms. In the preferred range the number of free ends lies between 018 and 0.34 per 100 silicon atoms. The optimum fluid molecule, with a molecular weight of 60,000 has 0.25 end groups per 100 silicon atoms; this figure remains essentially unchanged on curing. In the cured elastomer the average length of the free ends is between and 100 silicon atoms.
• the preferred rangeof fluids gives minimum cross-link densities of from 0.25 to 0.40 cross-links per 100 silicon atoms. Allowing for some cross-links due to coupling, the preferred range of cross-link density is from'0.25 to 0.50 cross-links per 100 silicon atoms.
• a typical prior art silicone elastomer made from a gum having 01 to 0.2 mole percent vinyl has a calculated minimum cross-link density of between 0.098 and 0.198.
• the novelty of the present elastomers does not reside solely in their high cross-link density, however, but in the combination of high cross-link density and high free end density.
• EXAMPLE 1 A mixture containing 100 parts of octamethylcyc'lotetra siloxane, 0.52 part of mixed cyclic methylvinylsiloxanes obtained from the hydrolysis product of methylvinyldichlorosilane, and 1.46 parts of a shortchain trimethylsilyl-endblocked polydimethylsiloxane having an average of 815 silicon atoms per molecule (endblocker), is heated to 85C. To this is added 0.2] part of a tetramethylammonium siloxanolate solution containing the equivalent of 6.2 percent of tetramethylammonium hydroxide.
• the viscosity of the mixture begins to increase in a few minutes and equilibration is complete in 1 hour at 85C.
• the temperature is then raised to about 140C. to destroy the catalyst.
• the product is then stripped for an hour under vacuum to remove a small amount of volatile matter, consisting primarily of an equilibrium quantity of cyclic siloxanes.
• the product contains 0.45 mole percent of methylvinylsiloxane units, which is essentially the same as in the initial mixture. It is a clear fluid with a viscosity of 12,000 cp at 25C.
• EXAMPLE 2 complete the recrystallization. It is then filtered through a Buchner funnel. The filter cake thus obtained is substantially dry, containing no more than about 10 percent of water and methanol. It is crushed and finally dried in a stream of nitrogen, giving a yield of recovered peroxide of percent.
• the recrystallized material when diluted to 0.08 percent in heptane, shows an percent absorbance at 260 nm and a 65 percent absorbance at 240 nm. Although the peroxide is of a pale buff color, the U.V. absorption is not significantly different from that of a pure white material obtained by repeated crystallization. This oncerecrystallized-material will be referred to as the peroxide of Example 2.
• EXAMPLE 3 One hundred parts of the fluid of Example 1 is heated to 55 C. To .this is added one half part of the peroxide of Example 2. It dissolvesquickly and does not recrystallize on cooling. U.V. absorption shows no decomposition of the peroxideA portion of the mixture is poured into the cavity of an impact absorber. The assembly is then heated. for 30 minutes in an oven at 450F., the internal temperature reaching amaximum of 410F. This is sufficient for complete cure of the fluid to a soft elastomer. The assembly is then placed in a dynamometer and subjected to repeated compression-retraction cycles, in which the test sample is allowed to cool to room temperature between cycles.
• the amplitude is such that virtually all of the elastomer is forced through the orifice in the firststroke, thereby being broken intofine particles. Theseparticles will flow back during the retraction phase.
• the stress-strain curve is virtually the same for all compressionre'traction cycles except the first, indicating that there is no further chemical or mechanical breakdown of the elastomer. ln each cycle, the energy absorption is sufficient to absorb an impact of 2,000 joules without bot-' toming out or transmitting an excessive force at any time during the cycle.
• a third portion is cured for 25 minutes at 350F. in the form of a 1-inch by 4-inch button and tested with the Shore A durometer. It is found to have a Shore A hardness of 12.
• EXAMPLES 4 TO 15 Fluids are prepared in accordance with the procedure of Example 1, except that the amounts of cyclic methylvinylsiloxane and endblocker are varied to give different viscosities and vinyl contents. After stripping samples are heated in a vacuum oven and found, by weight loss, to contain between 2.3 and 4.2 percent of residual volatile matter, which is an acceptable range.
• the fluid of Example 15 is the most difficult to strip, because of its relatively high viscosity and has the highest residual volatiles.
• Each fluid is mixed with 0.5 percent of the peroxide of Example 2 and cured at 350F. in accordance with Example 3 The results of the tests are illustrated in thefollowing table.
• EXAMPLE 16 Afluid having a viscosity of 87,000 cp and 0.20 mole percent Viny1" is cured in the Brabender Plasti- Corder at 350F. in accordance with Example 3 and gives a final torque of 1,200 metergrams which is acceptable.
• Example 3 is repeated except that 0.5 percent of the following catalysts are used:
• a silicone fluid curable to a hydraulic elastomer having a viscosity of from 1000 to 1,000,000 centipoises, comprising a copolymer of dimethylsiloxane units with 0.1 to 0.9 mole percent of methylvinylsiloxane units, the mole percent of methylvinylsiloxane units having a value of (4.8/log V) C, where V is the viscosity in centipoises and C is a number having a value of from 0.53 to 0.83, said copolymer having end groups selected from the class consisting of trimethylsiloxy, hydroxy and alkoxy.
• R is selected from the class consisting of alkyl radicals of from one to four carbon atoms, hydrogen and trimethylsilyl radicals, x is a number of from about 270 to about 2,700 and y is a number of from 0.00lx to 0.009x.
• silicone fluid of claim 2 wherein the viscosity is from 10,000 to 15,000 centipoises and the mole percent of methylvinylsiloxane units is approximately 0.45.
• silicone fluid of claim 1 which contains in addition 0.1 to 1.5 percent of a curing agent selected from the class consisting of tertiary alkyl peroxides and diperoxy ketals.
• the silicone fluid of claim 8 wherein the curing agent is bis-(t-butylperoxyisopropyl)-benzene.
• the silicone fluid of claim 11 wherein the curing agent has an ultraviolet absorbance at 240 nanometers that is no greater than at 260 nanometers.
• silicone fluid of claim 13 wherein the curing agent is 1,l-di-tbutylperoxy-3,3,5-trimethylcyclohexane.
• a process for curing the silicone fluid of claim 1 to a hydraulic elastomer which comprises heating said fluid with 0.1 to 1.5 percent of a curing agent selected from the class consisting of tertiary alkyl peroxides and diperoxy ketals at a temperature from C. to 210 C. for a time equal to at least one half-life of the curing agent.
• a curing agent selected from the class consisting of tertiary alkyl peroxides and diperoxy ketals at a temperature from C. to 210 C. for a time equal to at least one half-life of the curing agent.
• a hydraulic elastomer composed of a polydimethylsiloxane cross-linked by three-carbon bridges, in which the cross-link density is from 0.25 to 0.50 crosslinks per 100 silicon atoms, and in which there are from 0.074 to 0.74 free chain ends per 100 silicon atoms, said free ends having an average of from 50 to 100 silicon atoms each, said elastomer being characterized by a Shore A hardness of from 9 to 15, and being further characterized by its ability to absorb energy by flowing under pressure like a fluid.
• the hydraulic elastomer of claim 19 in the form of fine particles which are predominantly less than 1 millimeter in diameter.

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• Chemical & Material Sciences (AREA)
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• General Engineering & Computer Science (AREA)
• Organic Chemistry (AREA)
• Engineering & Computer Science (AREA)
• Medicinal Chemistry (AREA)
• Health & Medical Sciences (AREA)
• Polymers & Plastics (AREA)
• Mechanical Engineering (AREA)
• General Chemical & Material Sciences (AREA)
• Oil, Petroleum & Natural Gas (AREA)
• Compositions Of Macromolecular Compounds (AREA)
• Fluid-Damping Devices (AREA)
• Silicon Polymers (AREA)

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Cited By (52)

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• 1973
  • 1973-10-11 US US00405349A patent/US3843601A/en not_active Expired - Lifetime
• 1974
  • 1974-09-06 CA CA208,631A patent/CA1083617A/en not_active Expired
  • 1974-10-08 NL NL7413247A patent/NL7413247A/xx not_active Application Discontinuation
  • 1974-10-09 IT IT53435/74A patent/IT1021737B/it active
  • 1974-10-09 DE DE2448236A patent/DE2448236C3/de not_active Expired
  • 1974-10-10 AT AT817174A patent/AT340139B/de not_active IP Right Cessation
  • 1974-10-10 SE SE7412796A patent/SE418190B/xx unknown
  • 1974-10-10 GB GB43929/74A patent/GB1490204A/en not_active Expired
  • 1974-10-11 JP JP11703474A patent/JPS5539177B2/ja not_active Expired
  • 1974-10-11 BE BE149484A patent/BE821012A/xx not_active IP Right Cessation
  • 1974-10-11 FR FR7434245A patent/FR2247491B1/fr not_active Expired

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